Formula: C₈H₈N₆O₆ CAS: 569-58-4 EC No.: 209-304-3 M (Molar Mass): 284.19 g/mol D (Density): Not applicable mp (Melting Point): Decomposes without melting bp (Boiling Point): Not applicable Optical Rotation: Not applicable

Assay (as dry substance): ≥ 98.0 % Appearance: Dark reddish-brown to bronze powder or crystals. Solubility: Soluble in water giving a purple solution; soluble in dilute alkalies. Identification (Spectrophotometry): Aqueous solution shows characteristic absorption maxima at ~520 nm and ~540 nm (pH dependent). pH of Saturated Solution: ~9. Loss on Drying (at 105°C): ≤ 1.0 % Residue on Ignition: ≤ 0.5 % Chloride (Cl): ≤ 0.05 % Sulfate (SO₄): ≤ 0.05 % Heavy Metals (as Pb): ≤ 20 ppm Iron (Fe): ≤ 50 ppm Suitability as Calcium Indicator: Passes test (clear color change from pink to violet with Ca²⁺ at pH >12).